Pipe-cutting tool



Aug. 7', 1945. J. B. GILL ETAL 2,381,156

PIPE CUTTING TOOL Filed May 1'7, 1944 Ill/IA mnuunnnnunnuuu nnunnunuuuuiuunuuunuuv INVENTOR. J- B- GILL Patented Aug. 7, 1945 PIPE-CUTTING TOOL John B. Gill, San Francisco, and Telford L. Smith,

South San Francisco, Calif. Application May 17, 1944, Serial No. 535,958

Claims. The present invention relates to improvements in a pipe cutting tool and has particular reference to a. hand-operated tool intended for cutting asbestos-cement or cast-iron pipe.

The principal object of the invention is to provide a tool of the character described that is relatively simple in construction, efiic'ient in operation, and which may be readily adjusted to serve a relatively wide range of pipes of difi'erent diameters and different thicknesses.

A further object of the invention is to provide a pipe cutter of the chain-type adapted to be revolved around the pipe andcarrying a blade and guide means for causing'the blade to follow a true annular course around the pipe,

A still further object of the invention is to provide various adjusting means for the length of the chain, whereby the latter may be adjusted for pipes of widely different-and varying diameters, and again, is-capable of fine adjustment for tightening the same upon a pipe to which it has been roughly adjusted.

It is further proposed to provide novel means for turning the chain about the pipe by means of a handle, and to arrange the handle in such a way that the predominating part of a turning force exerted on the handle is translated into circumferential chain movement.

And finally, itis proposed to provide a pipe cutter that is particularly adapted for. cutting pipe of large diameter, is practical, of light weight, and adaptable for field operation, and that may readily be used on pipe disposed above the ground as well as on pipe lying in a trench and having relatively little clearance.

In the latter function it should be particu-' larly noted that the tool cuts a kerf and actually drawn'to-a radius smaller than that of the pipe removes a thickness of material at the cut, which, i

in underground operations, facilitates moval of the separate sections.

The tool may also be placed around the pipe the rein such a manner as to cut on a slight bias which allows one section to be lifted away from the other section at the cut in'a hinge movement.

Further objects and advantages of this invention will appear as the specification proceeds and the novel features thereof will be fully. set forth in the claims hereto appended.

The preferred form of the present invention is Figure 4, a rear view of the cutter blade used" in the device.

While the drawing illustrates only the preferred form of the invention,.it should. be understood that various changes or modifications may be made within the scope ofthe'claims hereto at-' tached, without departing from the spirit of the invention.

plurality of links of substantially similar construction, each link being in the shape of an are so as to curve away vfrom the pipe.

. Each link 3 consists of two side bars 4 held in spaced relation by one anotherby means of bolts or rivets 5 and spacing sleeves 6. The links are interconnected by. pivots ,1, which serve as axles:

or journals for rollers 8 having central tapered ridges 9.

The rollers are of considerable width, possibly about one inch for a pipe cutter of the range shown, and are of sufficient diameter to cause v the ends of the links to clear'the pipe.

The overall length of the chain is such, after adjustment, as to entirely surround the pipe, and

the chain may be fastened upon the pipe by means of a hook I0 on one end link fitting over the pivot shown at H, toform a larger are outside the normal course'of the chain, and by providing threaded means, such as the rod ii, for contracting and expanding thelarger arc.

The rod is reversely threaded at opposite ends to engage in similarly threaded bearings 53- mounted in the links on pivots I4 intermediate the lengths of the links. The threadedrod may be formed with a central hexagonal hub l5 for operation by a wrench or with a suitable handle l6. chain may be adjusted to fit a Wide range of different pipes.

One of the links carries a cutter l6 which may be of the type in common use in lathe operations for cutting stock. The cutter preferably is of the approximate widthof theridgesof the rollers and is mounted in the same transverse plane so as to follow the trail of the ridges; It is mounted in any suitable manner in a block I! which is positioned, with freedom of radial sliding movement,

in a yoke l8 rising from the link and which may be ied toward and away from the center of the pipe by means of a. screw i9 threaded in the upper end of the yoke. The screw has a suitable handle 20 for manipulating the same.

For turning the chain about the pipe, it is r'oposed to use the handle 2! and the brace 22, which In this manner the overall length of the- ,V

latter is pivoted to the handle, as at 23. The handle and the brace may be formed in a rigid unit, but a pivotal connection is preferred, since the latter allows of a certain amount of adjustment by providing a plurality of pivot holes 24, as shown.

vBoth the handle and the brace are made in the form of rectangular frames to conform to the link construction, the handle having an operating bar 25 at the free end thereof.

One end of the handle is pivoted to one of the link pivots, as at 26, while the brace is pivoted to a second link pivot 21, spaced from the former link pivot, preferably by the length of at least two links.

The handle and the brace are constructed principally withthe view of preventing buckling and of translating a turning force applied at the handle into circumferential chain movement. If, for instance, a single radial handle were applied to a single link, a turning force applied to the handle would cause the link to tilt, to dig into the pipe material at the forward end and to lift away from the pipe at the rearward end. This tilting movement is prevented by the double grip on two chain' pivots and also by the fact that at least one chain pivot is spanned by the manipulating means.

To avoid all tendency to buckle, the handle and the brace might be attached to chain pivots diametrically opposite each other, but this is difficult of accomplishment in view of the wide range of adjustment of the overall length of the chain, and also in view of the fact that such arrangement might take up too much room, particularly where the pipe to be cut is located in a place awkward of access, as in a trench.

Thus it is preferred to strike a compromise by placing the two points of attachment sufficiently far apart to render the buckling tendency negligible, with at least one pivot between the same, and still sufficiently close for convenience in handling.

In the form shown, with a chain of eight links and a pipe within'a range including a seven-inch pipe, the arrangement of the handle and the brace as shown, so as to span two links, is satisfactory. Where a pipe of much larger size is involved and the chain might, for instance, consist of fourteen links, the handle and the brace might span three links for satisfactory operation.

It is apparent that it may be desirable to apply a second handle and brace opposite the one shown to render one or the other,of the two handles available for operation,.depending upon ease of access.

The handle is preferably curved and arranged to run off in the direction of a tangent to the pipe, rather than in a radial direction, to facilitate application of the brace and to limit the tightened by means of one of the rods I5 to press the ridges 9 slightly into the pipe material.

Next the chain is turned around the pipe to cut a tracer mark. Since all the'links are rigid and of considerable width, the roller ridges will follow one another in a true course and cut a perfect circle around the pipe.

Successive alternate tightening and rotation will deepen the mark into a groove until a desired depth has been obtained. Thereupon, the cutter blade is screwed down to enter into cutting engagement with the pipe, and alternate rotation and feeding of the cutter blade will out the pipe material to the depth of the inner diameter. The ridges of the roller thus serve to guide the cutter blade and insure a smooth and perfect out,

If it is desired to make a cut at a slight angle to allow one section to swing away from the other, the chain may be wrapped about the-pipe to form the desired angle, which latter is limited, of course, by the width of the rollers as compared with the height of the ridges.

We claim:

1. In a pipe cutting tool, a chain adapted for placin around a pipe and comprising a plurality of links having pivots connecting the same, one of the pivots being lifted away from the pipe to cause adjacent links to project from the pipe for bringing the two opposite pivots of said links into closer proximity to one another and for reducing the overall length of the chain, and means for adjusting the spacing between the latter two pivots.

2. In a pipe cutting tool, a chain adapted for placing around a pipe and comprising a plurality of links having pivots connecting the same, one of the pivots being lifted away from the pipe to cause adjacent links to project from the pipe for bringing the two opposite pivots of said .links into closer proximity to one another and for reducing the overall length of the chain, and means for adjusting the spacing between the latter two pivots, the said means comprising reversely threaded bearings pivoted in the links and a rod bridging the links having reverse threads engaging in said bearings.

3. In a pipe cutting tool, a chain' adapted for placing around a pipe and comprising a plurality of links having pivots connecting the same, and means cooperating with selected links for drawing normally spaced pivots associated therewith toward one another for reducing the overall length of the chain.

4. In a pipe cutting tool, a chain adapted for placing around a pipe with freedom of rotary movement and comprising a plurality of links having pivots connecting the same, a cutter carried by the-chain, and means for revolving the chain about the pipe comprising a handle attached to the chain at circumferentially spaced points so as to straddle at least one of the pivots. 5. In a pipe cutting tool, a. chain adapted for placing around a pipe with freedom of rotary movement and comprising a plurality of links having pivots connecting the same, a cutter carried by the chain, and means for revolving the chain about the pipe comprising a handle attached to the chain at circumferentially spaced points so as to straddle at least two of the links.

' JOHN B. GILL.

TELFORD L. SMITH. 

